value is negative or is greater than the maximum length of the MemoryStream, where the maximum length is(MaxValue- origin), and origin is the index into the underlying buffer at which the stream starts.

If the specified value is less than the current length of the stream, the stream is truncated. If after the truncation the current position within the stream is past the end of the stream, the ReadByte method returns -1, the Read method reads zero bytes into the provided byte array, and Write and WriteByte methods append specified bytes at the end of the stream, increasing its length. If the specified value is larger than the current capacity and the stream is resizable, the capacity is increased, and the current position within the stream is unchanged. If the length is increased, the contents of the stream between the old and the new length are initialized to zeros.

Note A MemoryStream instance must support writing for this method to work. Use the CanWrite property to determine whether the current instance supports writing. For additional information, see CanWrite.